General Physics Questions about the 2 stroke setup

1) Yes, you can pedal with the engine engaged. This is one reason I prefer a multi-speed bicycle versus a single speed.

2) Yes, the (motor) chain will always turn the same speed as the rear wheel. Yes, this does create drag when pedaling with engine off. I pedal my bike often, again another reason I prefer a multi-speed. With a multi-speed pedaling is made a lot easier and choosing the correct gear can almost make it feel like there is no drag.

3) Yes, it easy to turn your motor on/off when you use a kill switch. I ride in heavy pedestrian traffic sometimes and often I turn my motor on or off depending on how heavy the traffic is.

x

From an engineering/physics perspective:

1) With the motor running - do you still pedal when the motor is running? Can you "assist" the motor while going up steep hills by pedaling, or vice-versa, does this even work? There are some extremely steep hills in the Pittsburgh area that I would potentially be going up and have doubts as to whether even a 66cc motor could haul my 200lb ass up by itself.

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I'm barely qualified for barstool engineering and the best I can do in physics is mixing fuel for my string trimmers.

Yes. you can pedal while an ht is running.
Yes. that's why we call them Motor Assisted Bicycles.
If the hills are Xtreme, why bother? You'd probably make a lot of noise and upset everyone. If you must, a shifter kit would allow the HT to climb almost anything within reason.
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2) With the motor turned off - this is the big question I have - I am having trouble seeing how the motor chain works when the motor is off. Does the chain always turn as the same speed as the rear wheel, or is it like the regular bike chain where the only time the chain is moving is when you are pedaling? I know that at the very least, the clutch would disengage the chain from the motor, but if the chain still moves as the bike is moving even with the motor turned off and the clutch out, does this create a lot of chain drag to overcome with regular pedaling?

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Typically, the drive chain is always engaged.
The latching clutch release lever is what disconnects the rear drive assembly from the crankshaft. Everything else always rotates, causing drag. IMO, MABs are not well designed for pedaling for more than a short distance. Very short.
There are other options, one of which is the fellow in OZ who sells a device for inserting D-ring pins into a sprocket connector plate, removal of them would allow the wheel to be pedaled free of the drive chain.
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3) Is it really as easy as advertised to turn the motor on and off as you are riding? My 2 mile commute would likely involve a great deal of switching the motor on and off as I go on streets and then ride through parks and bike paths. This is another reason I am curious about the chain drag question above.

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Sure it's easy to turn it off and on.
Engage the latching clutch lever and hit the kill switch.
Release the lever to continue on motor power.
There IS a lot of drag from the chain and drive system unless you employed that system from OZ, mentioned above.
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IMO

To me, for your 2 mile commute, considering you do not seem adverse to pedaling on those hills, I think you would be best served by a lever controlled string trimmer FD such as A_dam has posted.

It is totally free of the pedaling system when disengaged, and a real benefit all other times, with the exception of wet pavement.

n00b questions are very wise! We are here to help!
It provides you with the best options that may assure you of building the most useful motorized bicycle for your circumstances.
Get a second opinion on anything I say!

Best
rc

The drive chain is always engaged
and you can pedal with the engine engaged

Xixor said:

I am still very new to this project and am having some difficulty envisioning how exactly the bike will ride when set up with a two stroke motor - like the 49cc or 66cc grubee, jet, etc china kits.

From an engineering/physics perspective:

1) With the motor running - do you still pedal when the motor is running?Yes you can, I don't Can you "assist" the motor while going up steep hills by pedaling, or vice-versa, does this even work?
Peddle assisting climbing a hill, I don't have too. I'm running a 66cc and weigh 220#. I've climbed some steep hills in "Oak Mountain, Pelham, AL. But you still have that option. The ONLY modification on my engine is hardware modifications
There are some extremely steep hills in the Pittsburgh area that I would potentially be going up and have doubts as to whether even a 66cc motor could haul my 200lb ass up by itself.

2) With the motor turned off - this is the big question I have - I am having trouble seeing how the motor chain works when the motor is off. Does the chain always turn as the same speed as the rear wheel, or is it like the regular bike chain where the only time the chain is moving is when you are pedaling? Chain always moves when the rear wheel is moving. It is in direct proportion to the speed of the wheel. With the clutch engaged is how you start the engine, with the clutch disengaged, there will be some drag, but not too much for the majority of riders. I never peddle more then just starting the engine. The chain rides on the rear sprocket, and that sprocket is attached to the wheel and not the axle.
I know that at the very least, the clutch would disengage the chain from the motor (the clutch is what is disengaged, both wheel and engine sprocket always moves when the bike is moving), but if the chain still moves as the bike is moving even with the motor turned off and the clutch out, does this create a lot of chain drag to overcome with regular pedaling? With the clutch "OUT" (engaged) yes, with the clutch "IN" (disengaged)...no. Some but the bike can be peddled

3) Is it really as easy as advertised to turn the motor on and off as you are riding? My 2 mile commute would likely involve a great deal of switching the motor on and off as I go on streets and then ride through parks and bike paths. This is another reason I am curious about the chain drag question above. With a kill switch, killing the engine is at your finger tip, yes, it's that easy, as long as the kill switch works.

Sorry for the n00b questions but thanks for the help!

Click to expand...

No problem, I had some of those questions, unfortunately at that time I bought my 1st engine I wasn't a member of any MB forum.

Yes Number one thing to remember is you can pedal the bike with the clutch in or out but you can coast better with the clutch in it is also smoother since the engine is not engaged

the rear disconnects arent available anywhere in north america,and the link to hybriped is not working.
i did find someone that aparrently carries them,but they are out of stock.

i have had to pedal my bike from time to time,its not like you are dragging a sandbag behind you,but you will notice a little drag.a properly adjusted clutch and lubricated chain will minimize it.
i dont regret putting a motor on my bike for a second.if not pedaling is your goal,and great speed is not a concern,get yourself a 56 tooth sprocket.
it will make a world of difference.
the best part-100 miles,and i need to fill the tank.i made a three mile trip home on almost nothing left in my gas tank.like it was pretty much dry.

Tnx for that verification, tooljunkie.

Would anyone know of some other Total disconnect for least pedal resistance?

Tnx
rc

lol.
tom is correct,remove chain,clean grime off hands and then ride.
i was thinking about a spring tensioner and a couple hooks to hang chain on so i wouldnt have to remove it completly.

i really hoping i can find a simple disconnect other than the master link,as i do like to pedal - well a little.

I want to find a simple disconnect too, tooljunkie. I want to be able to make my bike quiet sometimes for pedaling. Rustycase said someone made a d-ring pin connecter that sounds perfect. It'd be nice to just pull the pin out and pedal around silently!

Ah, the motorbike vs pedal bike.

You will always feel the drag of the motor unless you disconnect it. You will always feel the weight of the motor.

Friction drives are the easiest to disconnect.

if i had a spring tensioner,i could flip chain off and hang it on pins mounted to the frame.
or another sprocket ring mounted to frame to hold chain out of the way.
would be easy to build,tensioner would be the hard part-unless i bought one.